Radiant Floor Heating Guide: What property owners should know

Cozy indoor temperatures and low energy bills even in the depths of winter are on the wish lists of many homeowners. Could underfloor heating be the answer?

We sat down with Ivan Milenovic, Pipelife's Heating and Cooling Business Development Manager, to debunk some myths about radiant floor heating and explore what property owners, contractors and real estate developers should know before deciding to invest in these systems.

_{What is radiant floor heating and how it works}

Radiant floor heating systems rely on embedded heating elements (electric cables or hot water pipes) that transfer heat to the surface, warming objects and people directly — rather than only heating the air.

When designed and installed correctly, radiant floors offer higher indoor comfort and energy efficiency compared to convection-based alternatives.

However, the system’s overall efficiency and performance will depend on the building insulation, the selected heat source, as well as the system design.

_{Hydronic or electric? Comparing types of radiant floor heat systems}

Two main types of radiant heat systems exist: hydronic (water-based) and electric. Both methods turn floors into efficient heat sources, creating a cozy atmosphere. Both technologies can also suit a variety of spaces, from bathrooms and kitchens to living areas and bedrooms. However, key differences must be considered before choosing the right solution.

• Hydronic heating systems operate by circulating warm water through a network of embedded pipes. They are compatible with various heat sources, from gas and electric boilers to district heating, geothermal and air-to-water heat pumps, making them adaptable to various home setups and energy preferences. When powered by renewable sources, hydronic heating systems offer very low operating costs and a reduced carbon footprint.
• Electric radiant systems utilize resistive heating cables powered directly by electricity. They are often more expensive to run, especially in regions with high electricity costs. However, they can be cheaper to install and have very fast response times, making them a great fit for small areas and single-room projects.

"Each case should be assessed individually, but, overall, hydronic floors tend to be more cost-effective for large areas and whole-house heating. Electric setups can be more convenient for equipping small spaces and single rooms," sums up Ivan Milenovic, Heating and Cooling Business Development Manager at Pipelife.

_{Planning and designing radiant floor heating systems}

Proper design is crucial for high performance and longevity of all radiant heat setups, and the first step is heat loss calculations, explains Milenovic.

“To provide a comfortable indoor climate, the heating system capacity needs to match or exceed the heat losses of the building, which will depend on the building envelope, size, floor plan, local climate and numerous other criteria. Only once the required system capacity is calculated, we can look at design options.”

Each floor heating system should be custom-made, taking into account:

• Local building codes and standards: National building regulations for both electric and hydronic heating vary significantly across Europe. Some countries and regions limit the use of electric underfloor heating as a primary heat source to promote energy efficiency. For hydronic heating systems, local regulations may apply to zoning.
• Available heat source: Electric radiant systems rely on the building’s electrical supply. Hydronic systems can be paired with gas, biomass or electric boilers, air-to-water and geothermal heat pumps and district heating.
• Circuit and zoning preferences: Loops are designed considering the size and heating requirements for various rooms. For hydronic floor heating systems, manifold placement must be considered, ideally in a central location to balance circuit lengths.
• Floor construction and height: Floor heating always adds height, which can vary from a few centimeters for electric and dry setups to 7-10 centimeters for wet systems. Height limits are rarely a limiting factor in new builds but must be carefully assessed in renovation projects.
• Floor covering: Materials like stone or ceramic tiles are effective heat conductors, whereas carpets or certain types of wood flooring can act as insulators and affect heat output.
• Furniture placement: The location of large furniture, such as kitchen cabinets, large beds or sofas, bookcases and wardrobes, should be accounted for in the design phase, as they can trap heat. To achieve maximum system efficiency, the loops should be designed around large furniture.

“At Pipelife, we provide design services for all customers. Our design team is in close contact with homeowners and contractors to evaluate the many parameters and factors that can affect the system performance and identify the best solution for each project.”

_{Planning radiant floor heating for new builds}

Hydronic radiant floor heating systems are now standard in energy-efficient housing developments across most Central, Western and Northern European countries. When paired with heat pumps, such setups offer very high indoor comfort and long-term savings on energy bills. 

“In new construction, the standard practice is the so-called ‘wet’ installation: the pipes are installed according to the design and then covered with screed. Once cured, the preferred floor finish is laid on top. Concrete mass effectively absorbs and stores heat, allowing for maximum efficiency and cost savings,” explains Milenovic.

Wet installations typically add 5 to 7 centimeters of height for tubing and screed. Depending on the preferred floor finish, the floor height may increase by about 10 centimeters.

_{Planning radiant floor heating for renovations}

Despite common misconceptions, radiant floor heating setups can be used in renovated buildings. The most common limiting factor is the ceiling height, explains Milenovic:

“The minimum indoor ceiling height for comfortable living should be at least 2.45 to 2.5 meters. In old homes with low ceilings, adding a standard wet installation on top of the existing concrete floor may not be ideal. In such cases, we recommend the so-called ‘dry’ installation or radiant wall heating.”

Dry (or low-profile) installation methods do not require covering pipes in screed and add only a couple of centimeters to the floor height. The pipes are simply clipped on a fixing board, or sometimes the existing concrete floor is grooved.

Apart from lower height requirements, dry installations can be completed faster and are lighter, making them a better fit for upper-level remodeling. However, they can be comparatively more expensive when it comes to material and long-term running costs.

“Where height and weight limits allow, or the existing concrete floor must be replaced anyway, wet radiant floors often turn out to be the most economical option in the long run.”

_{Best floor types for radiant heating}

Ceramic, porcelain and stone tiles are the best choices for radiant floor heating, as these materials have excellent thermal conductivity. Compared to other materials, tile floors heat faster and more evenly, ensuring optimal system efficiency and response times.

Still, a wide range of modern materials nowadays can be paired with floor heating systems.

“Some homeowners, for example, prefer wooden floors — and engineered hardwood planks, resistant to warping and cracking, are used in such projects. The same applies to vinyl and carpeted flooring; there are options designed for heated floors from these materials. The main thing is to choose a product that’s approved for or recommended to be used with underfloor heating by the manufacturer and to account for the respective flooring type in the system design,” sums up Milenovic.

_{Radiant floor heating installation and maintenance}

When installed correctly, quality floor heating systems serve for decades and require practically no maintenance from the homeowner. Electric setups typically last 30-40 years, whereas quality hydronic systems serve for over 50 years. Some components, such as boilers or thermostats, may degrade faster and require replacement.

“These are closed-loop systems, and the only connection occurs between the pipe and the manifold. Therefore, the possibility of leaks is very low, much lower compared to a standard hot and cold water distribution system,” explains Milenovic. “PERT/EVOH pipes, which are the gold standard for hydronic floor heating across Europe, are extremely durable and highly resistant to wear and mechanical damage.”

Negative experiences with radiant heating most commonly result from installation errors and deviations from the design. Choosing a reputable supplier and experienced installer is crucial to ensure even and reliable performance.

For electric setups, a licensed electrician is required to handle connections and ensure compliance with local building regulations.

For hydronic systems, a professional installer is needed not only to lay the pipes and connect them to a manifold, but also to balance and pressure-test the system.